use of angulates by yellow stone grizzly bears

8/14/2019 Use of Angulates by Yellow Stone Grizzly Bears

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Presented by :

YURIY SHEVCHUK2nd Years FWR Student

David J. Mattson


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IntroductionOutline:

Purpose of the study1. What? Why?

Location and features of interest1. Geographical location and landscape

2. General Characteristics Inventory

1. Data collection techniques

2. Structure of study

3. How were things done

Discovery1. Findings

2. Determinations

Conclusion


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The Purpose:

The primary purpose of the study was to estimatevariance of ungulate use by grizzly bears, as well as, todetermine how grizzlies use ungulates throughouttime.


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The Purpose (ctd.):

To determine relationships between the grizzly bearsand ungulates that are found within the YNP;

To collect enough data to analyze and evaluate keypoints from ungulate management perspective.

To understand grizzlys overall consumption ofungulates;


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Purpose (ctd):

To determine whether annual consumption ofungulates and relative frequency of predation on elkcalf were greater in 1984-1992, or 1977-1983; and

Whether use of ungulates was associated with use ofwhite-bark pine (Pinus albicaulis) seeds.

David J. Matson


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Use of ungulates and use of refuse

Where dumpswere accessible,bears got used tofeeding ongarbage, and losttheir naturalinstincts ofhunting.

Even scavengingdecreased becauseof availablegarbage


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1988 fire affects on Yellowstone

grizzly bears

in greater Yellowstone,1988 fire directly killed345 elk, 12 moose, 36deer, 9 bison, and 6 black

bears

Many grizzlies werefound scavenging on

carcasses of animals thatsuffered death from fire


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Alaska and Canada study

In parts of Alaska and Canada

ungulate were kept at low by heavypredation on ungulate calves bygrizzly bears .


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White-bark pine seeds vs.ungulates

Grizzlybears

White-bark pine

seedsungulates


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Location:

Yellowstone NationalPark (entire park area),

including six nationalforests in states of

1. Wyoming;

2. Idaho; and

3. Montana.

Area = 23,300 km

During 1977 -1992

(15 years)


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Location (ctd.):

!

0 70 140 210 28035Kilometers

1:1,505,936

!

0 70 140 210 28035Kilometers

1:1,505,936

>75% Coniferous forests >2100 m plateaus among highermountains

Cold winters vs. warm summers Mean annual temperature 0 C


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Methods:

Hypothesizing Capturing

Taking body

measurements

Air relocating

Radio tagging

Sub sampling

Investigating

Identifying

Comparing

Knight and Eberhardt (1985) & Blanchard and Knight (1991)


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Bear Capturing


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Measurements takingand identifying


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Relocating


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Radio tagging andapplying other

tagging methodsfor easieridentification and

to facilitate futuredata collection


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Releasing


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Yellowstone grizzly bear investigations were

focused on ungulates, rather than bears

Ungulates

Bears

FOCUS

Less

More


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Tracking

What was inferred about bear numbers and identities was based oncorrespondence of radio-tagged bears to bear signs found around carcasses.

track sizing droppings/feces

diggings beds

Predation indicators were signs of struggling, such as:

broken branches broken gouges internal hemorrhaging broken vertebra diagnostic claw marks

on hide disarticulation

hide manipulation bone fracturing relative locations of

hair, rumen and skeletalremains

Mattson & Knight (1982).


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Calculations total energy expenditures

total energetic cost per bear (EC, in KJ day^-1, whee 1 KJ = 0.239 kcal)

were estimated as: EC=AC(287 BM^0.712), where AC=2.7 for malesand 1.4 for females

basal metabolic rate

total energy derived from meat =0.88(22.8MT), where 0.88 ismetabolized energy as a proportion from gross energy, 22.8=KJ grossenergy available from 1 g. of meat, and MT=gram of meat estimated tohave been used by an average bear. EA/(EDEC) gave total activeactivity cost giving by meat, where AC is number of days between last

and first ratio-relocations at den sites (224 days for adult males and188 days for adult females)

Unbalanced ANOVA test was used to address hypotheses employingparametric techniques where data were normal or could be

normalized by transformations


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Total and monthly consumption

53%

24%

18%

4%

1%

Elk Bison Moose Domestic stock. Mule deer

Results


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Elk calf and domestic livestock

Scavenged elk


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Use of ungulates throughout seasons ofthe year

June-July

September-October

April-May

Ungulate consumption


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July-October (32%)

October (58% of total ungulate meat)

Other two seasons (2% and 5%, April-May, and June)

Both scavenging and predation on adult male ungulatesincreased from April-June (11%) to July and after (47%).

Predation on elk calves were most common in June, calvingseason (71%), followed by July-October (24%), and April-May (3%)

Predation contributed relatively little(9%) of total meat consumed in April-May


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Using ungulatesadult female elk were used less than expected and elk

calves were used more than expected by relative

availability during all seasons.Bison yearlings were underused during Jun-October

Edibles consumed from moose (46%) and elk

(43%)were obtained by predation

Highest LowestAdult moose Elk >6 months old

Elk


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Year differences

Consumption:

Greatest: Smallest:

1980 1981

1989 1986

1990

1991

Relative Frequency of Total Consumption:

Early years: Late years:

40% 27%

Elk calf predation:

23% 17%


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Pine seeds vs. ungulatesAnnual consumption of white-bark pine seeds was eitherhigh, or low because of the abrupt inflection inrelationship between bear use and seed crop size (Matson

and Reinhart, 1994).

Years were also classified as use, or non use based on a cutpoint of 20% frequency of pine seeds in grizzly bear feces(Mattson at al. 1992).

If years wee also classified by frequency of ungulate useduring June-October, with a cut point 8, then high level ofungulate and white-bark pine seed are mutually exclusive.

Similarly, frequency of ungulate use was 2.1x greaterduring years when grizzlies didnt use pine seedscompared to years when they did.


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References sited: Chapman. D. G.. and D. S. Robson. 1960. The analysis of

a catch curve. Biometrics 16:354-368.

Craighead. J. J.. F. C. Craighead. Jr.. and J. Summner. 1976.Reproductive cycles and rates in the grizzly bear. I'rsirs

arctos horribilis, of the Yellowstone ecosystem. Pages 337-

356 in M. R. Pelton. J. W. Lentfer. and G. E. Folk. Jr..

editors. Bears-their biology and management. International

Union for Conservation of Natural Resources Publication

New Series 40.

Craighead, J. J., J. R. Varney, and F. C. Craighead, Jr. 1974.

A population analysis ofthe Yellowstone grizzly bears. Bulletin

40. Montana Forest and Conservation Experiment

Station. University of Montana, Missoula. Montana. USA.

Eberhardt, L. L. 1977. Optimal policies for conservation oflarge mammals. with special reference to marine ecosystems.

Environmental Conservation 4(3):205-2 12.

Eberhardt, L. L.. and D. B. Siniff. 1977. Population dynamics

and marine mammal management. Journal of the Fisheries

Research Board of Canada 34: 183-1 90.

use of angulates by yellow stone grizzly bears

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